We will continue to make considerable use of our newly defined and characterized intestinal epithelial cell line. This tissue culture cell line will be extremely valuable in the examination of the effect of fasting, nutrient modification and hormones on surface membrane alterations and on transport proteins. We will also continue to direct our effort to the study of intestinal transport of sugars and amino acids, with a special emphasis on attempts to gain a better understanding of factors regulating transmembranes transport of these nutrients. Studies will involve comparisons of uptake by vesicles prepared from microvillus, basolateral and Golgi membranes. These membranes will also be treated with various agents (including cholate, Triton, dimethyl maleic anhydride) to solubilize and extract membrane proteins in order to prepare artificially reconstituted (liposomal) vesicles in the hope of identifying and isolating membrane proteins involved in sugar and amino acid transport.